Actuators, such as electric motors and hydraulic drives, are used in a very wide variety of sizes and designs in various application areas. It is customary, at least in the case of relatively large actuators, to detect specific operating parameters, for example the temperature of cooling liquid or the temperature of the windings of electric motors or electromagnets, via sensors. In this case, the sensors are mounted at measurement points and a connecting line which is associated with the respective sensor leads to an evaluation unit which processes the sensor data further and optionally also forwards it. On account of communication between the evaluation unit and an external controller via a data bus, the actuator can be operated as a function of the detected data. In this case, the data is transmitted from the evaluation unit to the controller by interrogations initiated by the controller.
Further sensors are required more and more frequently, specifically in electric motors and in particular relatively large electric motors. Therefore, separate sensors, for example, are used to additionally detect the temperatures of the rolling bearings or other bearing systems of the rotor of the motor, in addition to the cooling-water feed temperature and the cooling-water return temperature, winding temperatures, generated torque and the like. A separate data line to the evaluation unit is required for all of these further sensors. Furthermore, the evaluation unit has to be configured as a function of the connected sensors, and this means that each of these configurations requires its own control system in the evaluation unit, which is configured as a function of the connected sensor system and optionally further actuating means, in order to control and evaluate said control systems in an appropriate manner, particularly when an electric motor is used in a very wide variety of configurations.